Following SQL statement can be used to check if stored procedure named “SelectEmployee” exists in the active database and drop it if exists.

IF EXISTS (SELECT SystemObjects.Name
FROM SYS.OBJECTS SystemObjects 
WHERE SystemObjects.type = 'p' AND SystemObjects.Name = 'SelectEmployee')
BEGIN
DROP PROCEDURE SelectEmployee
END

Following SQL statement can be used to check if table name “Employee” exists in the database and drop it if exists.

IF EXISTS (SELECT * FROM Sys.Tables
WHERE name = 'Employee')
BEGIN
DROP TABLE Employee;
END

Following SQL statement checks to see if column “Address” exists in the “Employee” table. If the column does not exist it adds that column.

If Not Exists (Select * From Information_Schema.Columns 
               Where Table_Name = 'Employee' And Column_Name = 'Address')
Begin
    Alter Table Employee Add Address nvarchar(200)
End

Often we need to get all the Foreign Key constraints so that you can drop them by making dynamic queries and then re-add them. This is usually needed when you are writing some custom data migration tool in which case you drop all the foreign key constraints first, then populate data, and then you add the constraints again.

Whatever be the use case, following SQL query will give you details of all the foreign key constraints in the active database:

SELECT OBJECT_NAME(ForeignKeyColumn.Constraint_Object_ID) AS 'ForeignKey', OBJECT_NAME(ForeignKeyColumn.Parent_Object_ID) AS 'ForeighKeyTable', ParentColumn.name AS 'ForeighKeyColumn', OBJECT_NAME(ForeignKeyColumn.Referenced_Object_ID) AS 'PrimaryKeyTable', ReferencedColumn.Name AS 'PrimaryKeyColumn' 
FROM Sys.Foreign_Key_Columns ForeignKeyColumn
INNER JOIN Sys.All_Columns ParentColumn 
ON ForeignKeyColumn.Parent_Object_ID = ParentColumn.Object_ID
AND ForeignKeyColumn.Parent_Column_ID = ParentColumn.Column_ID
INNER JOIN Sys.All_Columns ReferencedColumn 
ON ForeignKeyColumn.Referenced_Object_ID = ReferencedColumn.Object_ID
AND ForeignKeyColumn.Referenced_Column_ID = ReferencedColumn.Column_ID 
ORDER BY OBJECT_NAME(ForeignKeyColumn.Referenced_Object_ID);

Following SQL query will list all the stored procedures and their definition in the active database:

SELECT SysObject.Name, SysModule.Definition
FROM Sys.Objects SysObject INNER JOIN Sys.Sql_Modules SysModule
ON SysObject.Object_ID = SysModule.Object_ID
WHERE SysObject.Type = 'p'
ORDER BY SysObject.Name;

Following SQL query gives you names of all the stored procedures in the active database:

SELECT SystemObjects.Name
FROM SYS.OBJECTS SystemObjects 
WHERE SystemObjects.type = 'p' 
ORDER BY SystemObjects.Name;

Following SQL query gives you names of all the tables in the currently active database:

SELECT Name FROM Sys.Tables

Sometimes, you get this error when installing SQL Server 2005. Following is what has fixed the issue for me:

• Go to windows services (Start->Run->services.msc) and start Windows Installer service if it is not already started. If you are not able to start Windows Installer service, run **msiexec /regserver **command from command prompt.

This SQL Server installation error occurs when you have applied compression on the installation folder. To fix this issue do the following:

1. Right click [Program Files]\Microsoft SQL Server Go to properties. Uncheck ‘Compress contents to save disk space’. This option is at different places on XP and Vista (Win 7) machines. But you should be able to find this from this screen.

This is one of the most common errors occurring when installing SQL Server Express 2005. This error occurs in different scenarios on different machine configurations.

One solution that works in all or most of the cases is to uninstall MSXML 6.0 and then install SQL Server. But this solution is not trivial either. Because, you cannot uninstall MSXML 6.0 from add/remove programs. Microsoft had published an utility called (msicuu2.exe) but they have recently removed this utility and I could not find any reliable source to download it from.

There is however a tool msizap that you can download and then use the following command to uninstall MSXML 6.0.

MsiZap T! {1A528690-6A2D-4BC5-B143-8C4AE8D19D96}

**

**

If you package SQL Server with you application, then you can put this command in the batch file and even automate this process.

There is also scenario where above command does not work. In that case i would suggest using some Install Cleanup utility. One of the tools that i have used and works quite well is Your Uninstaller.

An embedded database is a database management system (DBMS) which is tightly integrated with an application software. They do not require any separate installation and are hidden from the end user.

I recently consulted on a project to replace SQL Server with a lightweight embedded database. We had however kept our option open and were also looking at databases with less installation hiccups – the main motivation to get rid of SQL Server.

There are many embedded databases available today and to filter out the one you need its important to have some criteria. Following are the list of things we were looking for in the target database:

• No Installation Required (Preferably)

• SQL based.

• Performance should be as good as possible to SQL Server.

• RDBMS (So that we have less overhead when migrating from SQL Server)

• Can work in Server as well as embedded mode.

• Supports Stored Procedures (Not mandatory but good to have)

• Has .NET data access API.

• Costs reasonable for desktop applications with unlimited installation.

• Some renowned companies using them. This is to judge the stability.

• Easy migration path from SQL Server

Many of the requirements as you can see are for the sake of less overhead when we migrate from SQL Server. I went through many databases to find the one we needed. Many of the databases did not fit into our criteria just because they were not RDBMS or they didn’t have .NET APIs. Following databases are either non RDBMS or don’t have .NET APIs:

• MongoDB

• Casandra

• CouchDB

• Apache Derby

• Raima Database Manager

• SolidDB

• Oracle Berkley DB

• Valentina DB (ORDBMS)

• Informix Dynamic Server

Now, i will discuss the ones i really looked into.

• Firebird

• Both embedded and server flavors.

• RDBMS

• Has .NET data provider APIs.

• Stable. Built on the InterBase source code.

• Used by many companies. Lots of resources available on the web.

• Switching between server and embedded version mostly require change of connection string only.

• Supports stored procedures.

• Supports standard SQL.

• Performance is close to SQL Server.

• Open Source. Free for development and distribution.

Scimore DB

• Both embedded and server flavors. In the embedded version, they can even be configured to run in-process and out-of-process.

• RDBMS.

• Has .NET data provider APIs.

• Not very stable.

• No big name associated. Tough to find resources on the web.

• Switching between server and embedded mostly require change of connection string only.

• Supports stored procedures.

• Supports standard SQL.

• Performance is close to SQL Server.

• Free for development and distribution. Source code is also available at reasonable cost.

Elevate DB

• Both embedded and server flavors.

• RDBMS.

• Has .NET APIs.

• Supports stored procedures.

• Support standard SQL.

• No big names associated.

• Performance is slower than SQL Server.

ITTIA DB

• Embedded and server flavors.

• RDBMS

• Has .NET APIs.

• No stored procedures (It was supposed to be coming soon, i haven’t checked)

• Supports standard SQL.

• No big names associated.

• Performance is slower than SQL Server.

Effiproz

• Only embedded.

• RDBMS

• Has .NET APIs.

• Supports stored procedures.

• Free (MSPL)

SQL CE

• Only embedded

• RDBMS

• Has .NET APIs

• No stored procedures

• Free for distribution

• Supports standard SQL

• Performance of SELECT queries is considerably slower than SQL Server for large databases.

SQLite

• Only embedded

• RDBMS

• Has .NET APIs

• No stored procedures.

• Free for development and distribution

• Supports standard SQL

• Many big companies using it. Stable.

• Performance of SELECT queries is slower than SQL Server for large databases.

Vista DB

• Only embedded

• RDBMS

• Has .NET API. In fact, the database itself is in managed code.

• Supports stored procedures.

• Supports standard SQL.

• Performance is slower than SQL Server.

Empress Embedded Database

• Only embedded.

• RDBMS.

• Has .NET APIs.

• Supports stored procedure.

• Supports standard SQL

• Performance is slower than SQL Server.

InterBase

• Embedded edition only ideal for MySQL

• Not embedded

• RDBMS

• Has .NET API

• Supports stored procedures

• Supports standard SQL

• Performance is close to SQL Server.

• Not free when your application is not open.

Note that some databases might have enhanced their features so i would also suggest to check their latest set of supported features for any enhancements they might have come up with.